Easy removal of rare earth magnets from assemblies under repair

Quicker than mechanical removal that is now usually undertaken by hand No risk of contamination of the rest of the assembly with strongly magnetic particles No risk of damage to the magnet housing

Hydrogen decrepitation is a well known process for breaking rare earth alloys (eg- NdFeB) into powder. Hydrogen preferentially enters the rare earth rich grain boundaries in the material with an associated volume expansion. The structure cannot cope with such a large volume expansion and the grains break away from the material forming a fine powder. In this process hydrogen is introduced to one surface of a faulty magnet either as a jet or as a static gas by clamping a reaction cell onto the magnets surface. As decrepitation takes place the powder can be removed from the surface of the assembly by mechanical means or by using a magnetic field to attract the powder. Using this technique it is possible to recycle the powder and no damage is caused to the other magnets or to the underlying assembly.

Inventor: Baker, Ian | Wittmann, Markus Wolfgang | Hanna, James Anthony
Priority Number: US7815850B2
IPC Current: C22C003000 | C22C000100
US Class: 420581 | 148442
Assignee Applicant: The Trustees of Dartmouth College,Hanover
Title: High-strength nanostructured alloys
Usefulness: High-strength nanostructured alloys
Summary: For high-strength nanostructured alloy used for wear-resistance portion of engines, bearings, stators, washers, seals, rotors, fasteners, stamping plates, dies, valves, punches, and components of automobiles, aircrafts, drilling and mining.
Novelty: Intermetallic composition for high-strength nanostructured alloy used for wear-resistance portion of engines, is formed by spinodal decomposition process and contains preset amount of iron, nickel, manganese and aluminum

Chemical/Material

Chemical Composition

USA